Jet lag affects memory long after a return to a normal schedule.

A new study by researchers at the University of California has indicated that chronic jet lag alters the brain in ways that cause memory and learning problems long after one’s return to a regular 24-hour schedule.

Twice a week for four weeks, the researchers subjected female Syrian hamsters to six-hour time shifts — the equivalent of a New York-to-Paris airplane flight. During the last two weeks of jet lag and a month after recovery from it, the hamsters’ performance on learning and memory tasks was measured.

As expected, during the jet lag period, the hamsters had trouble learning simple tasks that the hamsters in the control group aced. What surprised the researchers was that these deficits persisted for a month after the hamsters returned to a regular day-night schedule.

What’s more, the experts found changes in the brain, specifically within the hippocampus, that plays an intricate role in memory processing. They found that, compared to hamsters in control group, the jet-lagged hamsters had only half the new neurons in the hippocampus following the month long exposure to jet lag.

Via Times of India